1. Field of the Invention
The present invention relates to an instrument for accessing the laryngeal area of the human body and, more particularly, to an improved laryngoscope for use in intubation.
2. Prior Art
Laryngoscopes are widely known and used in the medical field to facilitate endotracheal intubation of a patient during surgery to provide a positive air passageway for the administration of anesthesia and/or for the mechanical ventilation of the lungs of the patient. In the human anatomy, the epiglottis normally overlies the glottis opening into the larynx to prevent the passage of food into the trachea during eating; therefore, in endotracheal intubation, it is necessary to displace the epiglottis from the glottal opening to permit the air tube to be inserted into the trachea
Various laryngoscope constructions are known. The more widely used laryngoscopes consist of an elongate, rigid metal blade which is supportably attached to a handle and is inserted through the mouth of the patient into the pharyngeal area to displace the tongue and epiglottis and permit direct visualization of the glottis through the mouth opening. Such laryngoscopes are generally provided with a light source which is directed along the blade to illuminate the area beyond the distal end of the blade. Two general types of rigid blade constructions are the straight, or so called "Miller blade", and the slightly curved, or so called "MacIntosh blade." Curved laryngoscope blade constructions having light means to facilitate illumination of the areas of observation are described in U.S. Pat. Nos. 3,598,113; 3,643,654; 3,766,909; and 3,771,5I4.
The standard method for performing intubation of the trachea during surgery with rigid laryngoscope blades of the straight or slightly curved type is to place the patient in supine position, tilt the head backwards as far as possible, and distend the lower jaw to widely open the mouth. The rigid blade is then inserted through the mouth into the throat passageway to displace the tongue and epiglottis and expose the glottis of the patient. The larynx is then viewed through the mouth opening from an observation position just above and behind the head of the patient by sighting generally along the axis of the blade. The endotracheal tube is inserted, either orally or transnasally, and passed alongside the blade through the glottis.
Surgical instruments having means for indirect illumination and visualization of the pharyngeal areas of the body are known. U.S. Pat. Nos. 3,776,222 and 3,913,568 disclose devices for endotracheal intubation which comprise flexible or articulatable tubular probes having internal fiber optics for lighting and viewing the internal areas of the body. As disclosed in said patents, the probes carry a slidably removable endotracheal tube surrounding their outer surfaces and the probe is directly inserted into the trachea to position the tube. Such devices obviously require the use of relatively large diameter endotracheal tubes in order to be carried on the tubular probe, and their use necessarily is limited to patients with sufficiently large airway passages to accommodate the combined size of the probe and endotracheal tube. Additionally, due to the flexible nature of the probes, it is difficult to manipulate the probe to displace the tongue and epiglottis to permit direct insertion of the tube into the trachea.
U.S. Pat. No. 3,677,262 discloses a surgical instrument employing internal fiber optics in a rigid tube which carries an endotracheal tube surrounding its outer surface. The instrument not only requires the use of large endotracheal tubes with the limitations mentioned above, but its generally straight configuration requires hyperextension of the head and neck during use, as with the Miller and MacIntosh rigid, blade-type constructions described above.
U.S. Pat. No. 4,086,919 discloses a laryngoscope having an improved blade construction which is anatomically shaped which may be utilized for intubation of the trachea without disturbing the normal position of the head of a patient in supine position and without contacting the bony structure during use.
A problem arises; however, in the prior art in that it is relatively difficult to precisely place objects in the larynx and trachea regions of the patient.
A further problem arises in the prior art in that devices that merely push an endotracheal tube alongside a rigid blade do not have precise control of the leading portion of the tube. The result can be damage to the tissue of the patient during insertion and difficulty in precisely placing the tube.
A further problem arises in the prior art in that devices which slidably move endotracheal tubes around their outer surfaces are relatively large in cross-section size and may not be appropriate for all patients.
A further problem arises in the prior art in that devices which use internal fiber-optics for viewing areas in the patient and which slide intubation tubes around the outside circumference of the devices almost immediately obscure the operator's view.
A further problem arises in the prior art in that no special provision is made in using the devices for patients with individual health problems or for patients such as children which may require precise placement of an object or require a precise size tube for intubation.